Heat sources (e.g., stoves and fireplaces) in a structure present a risk of fire. Sensors may be used to monitor heat sources and provide an alert in the event of a fire and/or the presence of excessive heat. Sometimes a sensor will provide an unnecessary alert (e.g., a false alarm). Repeated instances of unneeded alerts can lead a user to ignore or disable the alerts, which defeats the purpose of the heat-source monitor and reduces user safety.